The paper presents the structure of invalidity due to diabetes in a large industrial town. The studies were based on the data collected from the Social Insurance Centre. The survey covered those examined for the first time by OKIZ in Lódź during 1970--1975, in whom invalidity due to diabetes has been certified. Altogether approx. 337 certificates have been analysed. In the population analysed women prevailed, coming to over 59%. The average age of the subjects was 52.1 years, and only 8% were younger than 40. The diabetes lasted for 8.2 years, on average and most (59%) were treated with insulin. The greatest group was that of the workers carrying on light physical work (45%), then those performing medium-hard work (34%) and the white-collar workers were the least group (21%). During the first 6 years of the disease approx. 72% of the patients have applied for a pension. They performed a medium-hard physical work and suffered from diabetes. Only 10% of white-collar workers applied for the pension. The diabetes itself, with no complications, seldom results in the need to stop work. Those with such diagnosis constituted merely 10% of the total population under survey. In all other subjects complications with accompanying diseases have been diagnosed. Mostly those were heart diseases and vascular complications (26%).